Adjusting channel state information reports to improve multi-radio coexistence

ABSTRACT

In a multi-radio user equipment (UE) various techniques may be used to buffer communications for a first radio access technology (RAT). A low channel quality for a second RAT is reported. An indication to halt downlink communications of the second RAT based on the reported low channel quality is received. The buffered communications by the first RAT when the second RAT downlink communications are halted are transmitted. An indication to the second RAT is sent to resume normal channel quality reporting.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119(e) to U.S.Provisional Patent Application No. 61/692,145, entitled ADJUSTINGCHANNEL STATE INFORMATION REPORTS TO IMPROVE MULTI-RADIO COEXISTENCE,filed on Aug. 22, 2012, in the names of BEHNAMFAR, et al., thedisclosure of which is expressly incorporated by reference herein in itsentirety.

BACKGROUND

1. Field

Aspects of the present disclosure relate generally to multi-radiotechniques and, more specifically, to coexistence techniques formulti-radio devices.

2. Background

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so on. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE)systems, and orthogonal frequency division multiple access (OFDMA)systems.

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the base stations to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the base stations. This communication linkmay be established via a single-in-single-out, multiple-in-single-out ora multiple-in-multiple out (MIMO) system.

Some conventional advanced devices include multiple radios fortransmitting/receiving using different Radio Access Technologies (RATs).Examples of RATs include, e.g., Universal Mobile TelecommunicationsSystem (UMTS), Global System for Mobile Communications (GSM), cdma2000,WiMAX, WLAN (e.g., WiFi), Bluetooth, LTE, and the like.

An example mobile device includes an LTE User Equipment (UE), such as afourth generation (4G) mobile phone. Such 4G phone may include variousradios to provide a variety of functions for the user. For purposes ofthis example, the 4G phone includes an LTE radio for voice and data, anIEEE 802.11 (WiFi) radio, a Global Positioning System (GPS) radio, and aBluetooth radio, where two of the above or all four may operatesimultaneously. While the different radios provide usefulfunctionalities for the phone, their inclusion in a single device givesrise to coexistence issues. Specifically, operation of one radio may insome cases interfere with operation of another radio through radiative,conductive, resource collision, and/or other interference mechanisms.Coexistence issues include such interference.

This is especially true for the LTE uplink channel, which is adjacent tothe Industrial Scientific and Medical (ISM) band and may causeinterference therewith. It is noted that Bluetooth and some Wireless LAN(WLAN) channels fall within the ISM band. In some instances, a Bluetootherror rate can become unacceptable when LTE is active in some channelsof Band 7 or even Band 40 for some Bluetooth channel conditions. Eventhough there is no significant degradation to LTE, simultaneousoperation with Bluetooth can result in disruption in voice servicesterminating in a Bluetooth headset. Such disruption may be unacceptableto the consumer. A similar issue exists when LTE transmissions interferewith GPS. Currently, there is no mechanism that can solve this issuesince LTE by itself does not experience any degradation

With reference specifically to LTE, it is noted that a UE communicateswith an evolved NodeB (eNB; e.g., a base station for a wirelesscommunications network) to inform the eNB of interference seen by the UEon the downlink. Furthermore, the eNB may be able to estimateinterference at the UE using a downlink error rate. In some instances,the eNB and the UE can cooperate to find a solution that reducesinterference at the UE, even interference due to radios within the UEitself. However, in conventional LTE, the interference estimatesregarding the downlink may not be adequate to comprehensively addressinterference.

In one instance, an LTE uplink signal interferes with a Bluetooth signalor WLAN signal. However, such interference is not reflected in thedownlink measurement reports at the eNB. As a result, unilateral actionon the part of the UE (e.g., moving the uplink signal to a differentchannel) may be thwarted by the eNB, which is not aware of the uplinkcoexistence issue and seeks to undo the unilateral action. For instance,even if the UE re-establishes the connection on a different frequencychannel, the network can still handover the UE back to the originalfrequency channel that was corrupted by the in-device interference. Thisis a likely scenario because the desired signal strength on thecorrupted channel may sometimes be higher than reflected in themeasurement reports of the new channel based on Reference SignalReceived Power (RSRP) to the eNB. Hence, a ping-pong effect of beingtransferred back and forth between the corrupted channel and the desiredchannel can happen if the eNB uses RSRP reports to make handoverdecisions.

Other unilateral action on the part of the UE, such as simply stoppinguplink communications without coordination of the eNB may cause powerloop malfunctions at the eNB. Additional issues that exist inconventional LTE include a general lack of ability on the part of the UEto suggest desired configurations as an alternative to configurationsthat have coexistence issues. For at least these reasons, uplinkcoexistence issues at the UE may remain unresolved for a long timeperiod, degrading performance and efficiency for other radios of the UE.

SUMMARY

In one aspect, a method of wireless communication is disclosed. Themethod includes buffering communications for a first radio accesstechnology (RAT). The method also includes reporting a low channelquality for a second RAT. The method further includes receiving anindication to halt second RAT downlink communications based on thereported low channel quality. The method also includes transmitting thebuffered communications by the first RAT when the second RAT downlinkcommunications are halted. The method further includes sending anindication to the second RAT to resume normal channel quality reporting.

In one aspect, a method of wireless communication is disclosed. Themethod includes detecting when potential communication time/frequencyresources of a second radio access technology (RAT) are within athreshold distance to communication time/frequency resources of a firstRAT. The method also includes reporting an altered channel quality forthe potential communication time/frequency resources of the second RATwhen the potential communication time/frequency resources of the secondRAT are within the threshold distance. The method further includescommunicating on the time/frequency resources of the first RAT.

Another aspect discloses an apparatus including means for bufferingcommunications for a first radio access technology (RAT). The apparatusalso includes means for reporting a low channel quality for a secondRAT. The apparatus further includes means for receiving an indication tohalt second RAT downlink communications based on the reported lowchannel quality. The apparatus also includes means for transmitting thebuffered communications by the first RAT when the second RAT downlinkcommunications are halted. The apparatus also includes means for sendingan indication to the second RAT to resume normal channel qualityreporting.

Another aspect discloses an apparatus including means for detecting whenpotential communication time/frequency resources of a second radioaccess technology (RAT) are within a threshold distance to communicationtime/frequency resources of a first RAT. The apparatus also includesmeans for reporting an altered channel quality for the potentialcommunication time/frequency resources of the second RAT when thepotential communication time/frequency resources of the second RAT arewithin the threshold distance. The apparatus further includes means forcommunicating on the time/frequency resources of the first RAT.

In another aspect, a computer program product for wirelesscommunications in a wireless network having a non-transitorycomputer-readable medium is disclosed. The computer readable medium hasnon-transitory program code recorded thereon which, when executed by theprocessor(s), causes the processor(s) to perform operations of bufferingcommunications for a first radio access technology (RAT). The programcode also causes the processor(s) to report a low channel quality for asecond RAT. The program code further causes the processor(s) to receivean indication to halt second RAT downlink communications based on thereported low channel quality. The program code also causes theprocessor(s) to transmit the buffered communications by the first RATwhen the second RAT downlink communications are halted. The program codefurther causes the processor(s) to send an indication to the second RATto resume normal channel quality reporting. The program code also causesthe processor(s) to report an altered channel quality for the potentialcommunication time/frequency resources of the second RAT when thepotential communication time/frequency resources of the second RAT arewithin the threshold distance.

In another aspect, a computer program product for wirelesscommunications in a wireless network having a non-transitorycomputer-readable medium is disclosed. The computer readable medium hasnon-transitory program code recorded thereon which, when executed by theprocessor(s), causes the processor(s) to perform operations of detectingwhen potential communication time/frequency resources of a second radioaccess technology (RAT) are within a threshold distance to communicationtime/frequency resources of a first RAT. The program code also causesthe processor(s) to report an altered channel quality for the potentialcommunication time/frequency resources of the second RAT when thepotential communication time/frequency resources of the second RAT arewithin the threshold distance. The program code further causes theprocessor(s) to communicate on the time/frequency resources of the firstRAT.

Another aspect discloses wireless communications having a memory and atleast one processor coupled to the memory. The processor(s) isconfigured to buffer communications for a first radio access technology(RAT). The processor(s) are also configured to report a low channelquality for a second RAT. The processor(s) are further configured toreceive an indication to halt second RAT downlink communications basedon the reported low channel quality. The processor(s) are alsoconfigured to transmit the buffered communications by the first RAT whenthe second RAT downlink communications are halted. The processor(s) arefurther configured to send an indication to the second RAT to resumenormal channel quality reporting. The processor(s) are also configuredto report an altered channel quality for the potential communicationtime/frequency resources of the second RAT when the potentialcommunication time/frequency resources of the second RAT are within thethreshold distance.

Another aspect discloses wireless communications having a memory and atleast one processor coupled to the memory. The processor(s) isconfigured to detect when potential communication time/frequencyresources of a second radio access technology (RAT) are within athreshold distance to communication time/frequency resources of a firstRAT. The processor(s) are also configured to report an altered channelquality for the potential communication time/frequency resources of thesecond RAT when the potential communication time/frequency resources ofthe second RAT are within the threshold distance. The processor(s) arefurther configured to communicate on the time/frequency resources of thefirst RAT.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, nature, and advantages of the present disclosure willbecome more apparent from the detailed description set forth below whentaken in conjunction with the drawings in which like referencecharacters identify correspondingly throughout.

FIG. 1 illustrates a multiple access wireless communication systemaccording to one aspect.

FIG. 2 is a block diagram of a communication system according to oneaspect.

FIG. 3 illustrates an exemplary frame structure in downlink Long TermEvolution (LTE) communications.

FIG. 4 is a block diagram conceptually illustrating an exemplary framestructure in uplink Long Term Evolution (LTE) communications.

FIG. 5 illustrates an example wireless communication environment.

FIG. 6 is a block diagram of an example design for a multi-radiowireless device.

FIG. 7 is graph showing respective potential collisions between sevenexample radios in a given decision period.

FIG. 8 is a diagram showing operation of an example Coexistence Manager(C×M) over time.

FIG. 9 is a block diagram illustrating adjacent frequency bands.

FIG. 10 is a block diagram of a system for providing support within awireless communication environment for multi-radio coexistencemanagement according to one aspect of the present disclosure.

FIG. 11 is a block diagram of a multi-radio wireless device according toone aspect of the disclosure.

FIG. 12 is a diagram illustrating sub-band and wideband channel qualityindicator (CQI) reporting.

FIG. 13 is a diagram illustrating manipulation of sub-band and CQIreporting to improve coexistence between mobile wireless service (MWS)and wireless connective network (WCN) radio access technologiesaccording to one aspect of the disclosure.

FIG. 14 is a block diagram illustrating modification of a soundingreference signal (SRS) to manipulate uplink scheduling grants accordingto one aspect of the disclosure.

FIG. 15A is a flow chart illustrating a method for manipulating sub-bandCQI reporting to improve coexistence between mobile wireless service(MWS) and wireless connective network (WCN) radio access technologiesaccording to one aspect of the present disclosure.

FIG. 15B is a flow chart illustrating a method for adapting the channelquality information reporting process according to one aspect of thepresent disclosure.

FIG. 16 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a multi-radio coexistencesystem.

DETAILED DESCRIPTION

Various aspects of the disclosure provide techniques to mitigatecoexistence issues in multi-radio devices, where significant in-devicecoexistence problems can exist between mobile wireless services (MWS)devices (e.g., LTE) and wireless network connectivity (WCN) devices thatoperate in the Industrial Scientific and Medical (ISM) bands (e.g., forBT/WLAN). As explained above, some coexistence issues persist because abase station is not aware of interference on the multi-radio device sidethat is experienced by other radios. To reduce the interference andmanage inter-radio coexistence, it is desirable to coordinate behaviorof the radios to reduce the time one radio is receiving while another,potentially interfering, radio is transmitting. One aspect of thepresent disclosure manipulates the MWS channel state informationreporting to improve coexistence between MWS and WCN radio accesstechnologies. In a further aspect of the present disclosure, amodification to a sounding reference signal manipulates uplinkscheduling grants to improve coexistence between MWS and WCN radioaccess technologies.

The techniques described herein can be used for various wirelesscommunication networks such as Code Division Multiple Access (CDMA)networks, Time Division Multiple Access (TDMA) networks, FrequencyDivision Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA)networks, Single-Carrier FDMA (SC-FDMA) networks, etc. The terms“networks” and “systems” are often used interchangeably. A CDMA networkcan implement a radio technology such as Universal Terrestrial RadioAccess (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) andLow Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856standards. A TDMA network can implement a radio technology such asGlobal System for Mobile Communications (GSM). An OFDMA network canimplement a radio technology such as Evolved UTRA (E-UTRA), IEEE 802.11,IEEE 802.16, IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM arepart of Universal Mobile Telecommunication System (UMTS). Long TermEvolution (LTE) is an upcoming release of UMTS that uses E-UTRA. UTRA,E-UTRA, GSM, UMTS and LTE are described in documents from anorganization named “3^(rd) Generation Partnership Project” (3GPP).CDMA2000 is described in documents from an organization named “3^(rd)Generation Partnership Project 2” (3GPP2). These various radiotechnologies and standards are known in the art. For clarity, certainaspects of the techniques are described below for LTE, and LTEterminology is used in portions of the description below.

Single carrier frequency division multiple access (SC-FDMA), whichutilizes single carrier modulation and frequency domain equalization isa technique that can be utilized with various aspects described herein.SC-FDMA has similar performance and essentially the same overallcomplexity as those of an OFDMA system. SC-FDMA signal has lowerpeak-to-average power ratio (PAPR) because of its inherent singlecarrier structure. SC-FDMA has drawn great attention, especially in theuplink communications where lower PAPR greatly benefits the mobileterminal in terms of transmit power efficiency. It is currently aworking assumption for an uplink multiple access scheme in 3GPP LongTerm Evolution (LTE), or Evolved UTRA.

Referring to FIG. 1, a multiple access wireless communication systemaccording to one aspect is illustrated. An evolved Node B 100 (eNB)includes a computer 115 that has processing resources and memoryresources to manage the LTE communications by allocating resources andparameters, granting/denying requests from user equipment, and/or thelike. The eNB 100 also has multiple antenna groups, one group includingantenna 104 and antenna 106, another group including antenna 108 andantenna 110, and an additional group including antenna 112 and antenna114. In FIG. 1, only two antennas are shown for each antenna group,however, more or fewer antennas can be utilized for each antenna group.A User Equipment (UE) 116 (also referred to as an Access Terminal (AT))is in communication with antennas 112 and 114, while antennas 112 and114 transmit information to the UE 116 over an uplink (UL) 188. The UE122 is in communication with antennas 106 and 108, while antennas 106and 108 transmit information to the UE 122 over a downlink (DL) 126 andreceive information from the UE 122 over an uplink 124. In a frequencydivision duplex (FDD) system, communication links 118, 120, 124 and 126can use different frequencies for communication. For example, thedownlink 120 can use a different frequency than used by the uplink 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the eNB. In this aspect,respective antenna groups are designed to communicate to UEs in a sectorof the areas covered by the eNB 100.

In communication over the downlinks 120 and 126, the transmittingantennas of the eNB 100 utilize beamforming to improve thesignal-to-noise ratio of the uplinks for the different UEs 116 and 122.Also, an eNB using beamforming to transmit to UEs scattered randomlythrough its coverage causes less interference to UEs in neighboringcells than a UE transmitting through a single antenna to all its UEs.

An eNB can be a fixed station used for communicating with the terminalsand can also be referred to as an access point, base station, or someother terminology. A UE can also be called an access terminal, awireless communication device, terminal, or some other terminology.

FIG. 2 is a block diagram of an aspect of a transmitter system 210 (alsoknown as an eNB) and a receiver system 250 (also known as a UE) in aMIMO system 200. In some instances, both a UE and an eNB each have atransceiver that includes a transmitter system and a receiver system. Atthe transmitter system 210, traffic data for a number of data streams isprovided from a data source 212 to a transmit (TX) data processor 214.

A MIMO system employs multiple (N_(T)) transmit antennas and multiple(N_(R)) receive antennas for data transmission. A MIMO channel formed bythe N_(T) transmit and N_(R) receive antennas may be decomposed intoN_(S) independent channels, which are also referred to as spatialchannels, wherein N_(S)≦min{N_(T), N_(R)}. Each of the N_(S) independentchannels corresponds to a dimension. The MIMO system can provideimproved performance (e.g., higher throughput and/or greaterreliability) if the additional dimensionalities created by the multipletransmit and receive antennas are utilized.

A MIMO system supports time division duplex (TDD) and frequency divisionduplex (FDD) systems. In a TDD system, the uplink and downlinktransmissions are on the same frequency region so that the reciprocityprinciple allows the estimation of the downlink channel from the uplinkchannel. This enables the eNB to extract transmit beamforming gain onthe downlink when multiple antennas are available at the eNB.

In an aspect, each data stream is transmitted over a respective transmitantenna. The TX data processor 214 formats, codes, and interleaves thetraffic data for each data stream based on a particular coding schemeselected for that data stream to provide coded data.

The coded data for each data stream can be multiplexed with pilot datausing OFDM techniques. The pilot data is a known data pattern processedin a known manner and can be used at the receiver system to estimate thechannel response. The multiplexed pilot and coded data for each datastream is then modulated (e.g., symbol mapped) based on a particularmodulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for thatdata stream to provide modulation symbols. The data rate, coding, andmodulation for each data stream can be determined by instructionsperformed by a processor 230 operating with a memory 232.

The modulation symbols for respective data streams are then provided toa TX MIMO processor 220, which can further process the modulationsymbols (e.g., for OFDM). The TX MIMO processor 220 then provides N_(T)modulation symbol streams to N_(T) transmitters (TMTR) 222 a through 222t. In certain aspects, the TX MIMO processor 220 applies beamformingweights to the symbols of the data streams and to the antenna from whichthe symbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from the transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At a receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(R) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by the RX data processor 260 is complementary to theprocessing performed by the TX MIMO processor 220 and the TX dataprocessor 214 at the transmitter system 210.

A processor 270 (operating with a memory 272) periodically determineswhich pre-coding matrix to use (discussed below). The processor 270formulates an uplink message having a matrix index portion and a rankvalue portion.

The uplink message can include various types of information regardingthe communication link and/or the received data stream. The uplinkmessage is then processed by a TX data processor 238, which alsoreceives traffic data for a number of data streams from a data source236, modulated by a modulator 280, conditioned by transmitters 254 athrough 254 r, and transmitted back to the transmitter system 210.

At the transmitter system 210, the modulated signals from the receiversystem 250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by an RX data processor242 to extract the uplink message transmitted by the receiver system250. The processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights, then processes the extractedmessage.

FIG. 3 is a block diagram conceptually illustrating an exemplary framestructure in downlink Long Term Evolution (LTE) communications. Thetransmission timeline for the downlink may be partitioned into units ofradio frames. Each radio frame may have a predetermined duration (e.g.,10 milliseconds (ms)) and may be partitioned into 10 subframes withindices of 0 through 9. Each subframe may include two slots. Each radioframe may thus include 20 slots with indices of 0 through 19. Each slotmay include L symbol periods, e.g., 7 symbol periods for a normal cyclicprefix (as shown in FIG. 3) or 6 symbol periods for an extended cyclicprefix. The 2L symbol periods in each subframe may be assigned indicesof 0 through 2L−1. The available time frequency resources may bepartitioned into resource blocks. Each resource block may cover Nsubcarriers (e.g., 12 subcarriers) in one slot.

In LTE, an eNB may send a Primary Synchronization Signal (PSS) and aSecondary Synchronization Signal (SSS) for each cell in the eNB. The PSSand SSS may be sent in symbol periods 6 and 5, respectively, in each ofsubframes 0 and 5 of each radio frame with the normal cyclic prefix, asshown in FIG. 3. The synchronization signals may be used by UEs for celldetection and acquisition. The eNB may send a Physical Broadcast Channel(PBCH) in symbol periods 0 to 3 in slot 1 of subframe 0. The PBCH maycarry certain system information.

The eNB may send a Cell-specific Reference Signal (CRS) for each cell inthe eNB. The CRS may be sent in symbols 0, 1, and 4 of each slot in caseof the normal cyclic prefix, and in symbols 0, 1, and 3 of each slot incase of the extended cyclic prefix. The CRS may be used by UEs forcoherent demodulation of physical channels, timing and frequencytracking, Radio Link Monitoring (RLM), Reference Signal Received Power(RSRP), and Reference Signal Received Quality (RSRQ) measurements, etc.

The eNB may send a Physical Control Format Indicator Channel (PCFICH) inthe first symbol period of each subframe, as seen in FIG. 3. The PCFICHmay convey the number of symbol periods (M) used for control channels,where M may be equal to 1, 2 or 3 and may change from subframe tosubframe. M may also be equal to 4 for a small system bandwidth, e.g.,with less than 10 resource blocks. In the example shown in FIG. 3, M=3.The eNB may send a Physical HARQ Indicator Channel (PHICH) and aPhysical Downlink Control Channel (PDCCH) in the first M symbol periodsof each subframe. The PDCCH and PHICH are also included in the firstthree symbol periods in the example shown in FIG. 3. The PHICH may carryinformation to support Hybrid Automatic Repeat Request (HARQ). The PDCCHmay carry information on resource allocation for UEs and controlinformation for downlink channels. The eNB may send a Physical DownlinkShared Channel (PDSCH) in the remaining symbol periods of each subframe.The PDSCH may carry data for UEs scheduled for data transmission on thedownlink. The various signals and channels in LTE are described in 3GPPTS 36.211, entitled “Evolved Universal Terrestrial Radio Access(E-UTRA); Physical Channels and Modulation,” which is publiclyavailable.

The eNB may send the PSS, SSS and PBCH in the center 1.08 MHz of thesystem bandwidth used by the eNB. The eNB may send the PCFICH and PHICHacross the entire system bandwidth in each symbol period in which thesechannels are sent. The eNB may send the PDCCH to groups of UEs incertain portions of the system bandwidth. The eNB may send the PDSCH tospecific UEs in specific portions of the system bandwidth. The eNB maysend the PSS, SSS, PBCH, PCFICH and PHICH in a broadcast manner to allUEs, may send the PDCCH in a unicast manner to specific UEs, and mayalso send the PDSCH in a unicast manner to specific UEs.

A number of resource elements may be available in each symbol period.Each resource element may cover one subcarrier in one symbol period andmay be used to send one modulation symbol, which may be a real orcomplex value. Resource elements not used for a reference signal in eachsymbol period may be arranged into resource element groups (REGs). EachREG may include four resource elements in one symbol period. The PCFICHmay occupy four REGs, which may be spaced approximately equally acrossfrequency, in symbol period 0. The PHICH may occupy three REGs, whichmay be spread across frequency, in one or more configurable symbolperiods. For example, the three REGs for the PHICH may all belong insymbol period 0 or may be spread in symbol periods 0, 1 and 2. The PDCCHmay occupy 9, 18, 32 or 64 REGs, which may be selected from theavailable REGs, in the first M symbol periods. Only certain combinationsof REGs may be allowed for the PDCCH.

A UE may know the specific REGs used for the PHICH and the PCFICH. TheUE may search different combinations of REGs for the PDCCH. The numberof combinations to search is typically less than the number of allowedcombinations for the PDCCH. An eNB may send the PDCCH to the UE in anyof the combinations that the UE will search.

FIG. 4 is a block diagram conceptually illustrating an exemplary framestructure in uplink Long Term Evolution (LTE) communications. Theavailable Resource Blocks (RBs) for the uplink may be partitioned into adata section and a control section. The control section may be formed atthe two edges of the system bandwidth and may have a configurable size.The resource blocks in the control section may be assigned to UEs fortransmission of control information. The data section may include allresource blocks not included in the control section. The design in FIG.4 results in the data section including contiguous subcarriers, whichmay allow a single UE to be assigned all of the contiguous subcarriersin the data section.

A UE may be assigned resource blocks in the control section to transmitcontrol information to an eNB. The UE may also be assigned resourceblocks in the data section to transmit data to the eNodeB. The UE maytransmit control information in a Physical Uplink Control Channel(PUCCH) on the assigned resource blocks in the control section. The UEmay transmit only data or both data and control information in aPhysical Uplink Shared Channel (PUSCH) on the assigned resource blocksin the data section. An uplink transmission may span both slots of asubframe and may hop across frequency as shown in FIG. 4.

The PSS, SSS, CRS, PBCH, PUCCH and PUSCH in LTE are described in 3GPP TS36.211, entitled “Evolved Universal Terrestrial Radio Access (E-UTRA);Physical Channels and Modulation,” which is publicly available.

In an aspect, described herein are systems and methods for providingsupport within a wireless communication environment, such as a 3GPP LTEenvironment or the like, to facilitate multi-radio coexistencesolutions.

Referring now to FIG. 5, illustrated is an example wirelesscommunication environment 500 in which various aspects described hereincan function. The wireless communication environment 500 can include awireless device 510, which can be capable of communicating with multiplecommunication systems. These systems can include, for example, one ormore cellular systems 520 and/or 530, one or more WLAN systems 540and/or 550, one or more wireless personal area network (WPAN) systems560, one or more broadcast systems 570, one or more satellitepositioning systems 580, other systems not shown in FIG. 5, or anycombination thereof. It should be appreciated that in the followingdescription the terms “network” and “system” are often usedinterchangeably.

The cellular systems 520 and 530 can each be a CDMA, TDMA, FDMA, OFDMA,Single Carrier FDMA (SC-FDMA), or other suitable system. A CDMA systemcan implement a radio technology such as Universal Terrestrial RadioAccess (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) andother variants of CDMA. Moreover, cdma2000 covers IS-2000 (CDMA2000 1X),IS-95 and IS-856 (HRPD) standards. A TDMA system can implement a radiotechnology such as Global System for Mobile Communications (GSM),Digital Advanced Mobile Phone System (D-AMPS), etc. An OFDMA system canimplement a radio technology such as Evolved UTRA (E-UTRA), Ultra MobileBroadband (UMB), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc.UTRA and E-UTRA are part of Universal Mobile Telecommunication System(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are newreleases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSMare described in documents from an organization named “3^(rd) GenerationPartnership Project” (3GPP). cdma2000 and UMB are described in documentsfrom an organization named “3^(rd) Generation Partnership Project 2”(3GPP2). In an aspect, the cellular system 520 can include a number ofbase stations 522, which can support bi-directional communication forwireless devices within their coverage. Similarly, the cellular system530 can include a number of base stations 532 that can supportbi-directional communication for wireless devices within their coverage.

WLAN systems 540 and 550 can respectively implement radio technologiessuch as IEEE 802.11 (WiFi), Hiperlan, etc. The WLAN system 540 caninclude one or more access points 542 that can support bi-directionalcommunication. Similarly, the WLAN system 550 can include one or moreaccess points 552 that can support bi-directional communication. TheWPAN system 560 can implement a radio technology such as Bluetooth (BT),IEEE 802.15, etc. Further, the WPAN system 560 can supportbi-directional communication for various devices such as wireless device510, a headset 562, a computer 564, a mouse 566, or the like.

The broadcast system 570 can be a television (TV) broadcast system, afrequency modulation (FM) broadcast system, a digital broadcast system,etc. A digital broadcast system can implement a radio technology such asMediaFLO™, Digital Video Broadcasting for Handhelds (DVB-H), IntegratedServices Digital Broadcasting for Terrestrial Television Broadcasting(ISDB-T), or the like. Further, the broadcast system 570 can include oneor more broadcast stations 572 that can support one-way communication.

The satellite positioning system 580 can be the United States GlobalPositioning System (GPS), the European Galileo system, the RussianGLONASS system, the Quasi-Zenith Satellite System (QZSS) over Japan, theIndian Regional Navigational Satellite System (IRNSS) over India, theBeidou system over China, and/or any other suitable system. Further, thesatellite positioning system 580 can include a number of satellites 582that transmit signals for position determination.

In an aspect, the wireless device 510 can be stationary or mobile andcan also be referred to as a user equipment (UE), a mobile station, amobile equipment, a terminal, an access terminal, a subscriber unit, astation, etc. The wireless device 510 can be cellular phone, a personaldigital assistance (PDA), a wireless modem, a handheld device, a laptopcomputer, a cordless phone, a wireless local loop (WLL) station, etc. Inaddition, a wireless device 510 can engage in two-way communication withthe cellular system 520 and/or 530, the WLAN system 540 and/or 550,devices with the WPAN system 560, and/or any other suitable systems(s)and/or devices(s). The wireless device 510 can additionally oralternatively receive signals from the broadcast system 570 and/orsatellite positioning system 580. In general, it can be appreciated thatthe wireless device 510 can communicate with any number of systems atany given moment. Also, the wireless device 510 may experiencecoexistence issues among various ones of its constituent radio devicesthat operate at the same time. Accordingly, device 510 includes acoexistence manager (C×M, not shown) that has a functional module todetect and mitigate coexistence issues, as explained further below.

Turning next to FIG. 6, a block diagram is provided that illustrates anexample design for a multi-radio wireless device 600 and may be used asan implementation of the radio 510 of FIG. 5. As FIG. 6 illustrates, thewireless device 600 can include N radios 620 a through 620 n, which canbe coupled to N antennas 610 a through 610 n, respectively, where N canbe any integer value. It should be appreciated, however, that respectiveradios 620 can be coupled to any number of antennas 610 and thatmultiple radios 620 can also share a given antenna 610.

In general, a radio 620 can be a unit that radiates or emits energy inan electromagnetic spectrum, receives energy in an electromagneticspectrum, or generates energy that propagates via conductive means. Byway of example, a radio 620 can be a unit that transmits a signal to asystem or a device or a unit that receives signals from a system ordevice. Accordingly, it can be appreciated that a radio 620 can beutilized to support wireless communication. In another example, a radio620 can also be a unit (e.g., a screen on a computer, a circuit board,etc.) that emits noise, which can impact the performance of otherradios. Accordingly, it can be further appreciated that a radio 620 canalso be a unit that emits noise and interference without supportingwireless communication.

In an aspect, respective radios 620 can support communication with oneor more systems. Multiple radios 620 can additionally or alternativelybe used for a given system, e.g., to transmit or receive on differentfrequency bands (e.g., cellular and PCS bands).

In another aspect, a digital processor 630 can be coupled to radios 620a through 620 n and can perform various functions, such as processingfor data being transmitted or received via the radios 620. Theprocessing for each radio 620 can be dependent on the radio technologysupported by that radio and can include encryption, encoding,modulation, etc., for a transmitter; demodulation, decoding, decryption,etc., for a receiver, or the like. In one example, the digital processor630 can include a coexistence manager (C×M) 640 that can controloperation of the radios 620 in order to improve the performance of thewireless device 600 as generally described herein. The coexistencemanager 640 can have access to a database 644, which can storeinformation used to control the operation of the radios 620. Asexplained further below, the coexistence manager 640 can be adapted fora variety of techniques to decrease interference between the radios. Inone example, the coexistence manager 640 requests a measurement gappattern or DRX cycle that allows an ISM radio to communicate duringperiods of LTE inactivity.

For simplicity, digital processor 630 is shown in FIG. 6 as a singleprocessor. However, it should be appreciated that the digital processor630 can include any number of processors, controllers, memories, etc. Inone example, a controller/processor 650 can direct the operation ofvarious units within the wireless device 600. Additionally oralternatively, a memory 652 can store program codes and data for thewireless device 600. The digital processor 630, controller/processor650, and memory 652 can be implemented on one or more integratedcircuits (ICs), application specific integrated circuits (ASICs), etc.By way of specific, non-limiting example, the digital processor 630 canbe implemented on a Mobile Station Modem (MSM) ASIC.

In an aspect, the coexistence manager 640 can manage operation ofrespective radios 620 utilized by wireless device 600 in order to avoidinterference and/or other performance degradation associated withcollisions between respective radios 620. Coexistence manager 640 mayperform one or more processes, such as those illustrated in FIG. 15. Byway of further illustration, a graph 700 in FIG. 7 represents respectivepotential collisions between seven example radios in a given decisionperiod. In the example shown in graph 700, the seven radios include aWLAN transmitter (Tw), an LTE transmitter (Tl), an FM transmitter (TO, aGSM/WCDMA transmitter (Tc/Tw), an LTE receiver (Rl), a Bluetoothreceiver (Rb), and a GPS receiver (Rg). The four transmitters arerepresented by four nodes on the left side of the graph 700. The fourreceivers are represented by three nodes on the right side of the graph700.

A potential collision between a transmitter and a receiver isrepresented on the graph 700 by a branch connecting the node for thetransmitter and the node for the receiver. Accordingly, in the exampleshown in the graph 700, collisions may exist between (1) the WLANtransmitter (Tw) and the Bluetooth receiver (Rb); (2) the LTEtransmitter (Tl) and the Bluetooth receiver (Rb); (3) the WLANtransmitter (Tw) and the LTE receiver (Rl); (4) the FM transmitter (Tf)and the GPS receiver (Rg); (5) a WLAN transmitter (Tw), a GSM/WCDMAtransmitter (Tc/Tw), and a GPS receiver (Rg).

In one aspect, an example coexistence manager 640 can operate in time ina manner such as that shown by diagram 800 in FIG. 8. As diagram 800illustrates, a timeline for coexistence manager operation can be dividedinto Decision Units (DUs), which can be any suitable uniform ornon-uniform length (e.g., 100 μs) where notifications are processed, anda response phase (e.g., 20 μs) where commands are provided to variousradios 620 and/or other operations are performed based on actions takenin the evaluation phase. In one example, the timeline shown in thediagram 800 can have a latency parameter defined by a worst caseoperation of the timeline, e.g., the timing of a response in the casethat a notification is obtained from a given radio immediately followingtermination of the notification phase in a given DU.

As shown in FIG. 9, Long Term Evolution (LTE) in band 7 (for frequencydivision duplex (FDD) uplink), band 40 (for time division duplex (TDD)communication), and band 38 (for TDD downlink) is adjacent to the 2.4GHz Industrial Scientific and Medical (ISM) band used by Bluetooth (BT)and Wireless Local Area Network (WLAN) technologies. Frequency planningfor these bands is such that there is limited or no guard bandpermitting traditional filtering solutions to avoid interference atadjacent frequencies. For example, a 20 MHz guard band exists betweenISM and band 7, but no guard band exists between ISM and band 40.

To be compliant with appropriate standards, communication devicesoperating over a particular band are to be operable over the entirespecified frequency range. For example, in order to be LTE compliant, amobile station/user equipment should be able to communicate across theentirety of both band 40 (2300-2400 MHz) and band 7 (2500-2570 MHz) asdefined by the 3rd Generation Partnership Project (3GPP). Without asufficient guard band, devices employ filters that overlap into otherbands causing band interference. Because band 40 filters are 100 MHzwide to cover the entire band, the rollover from those filters crossesover into the ISM band causing interference. Similarly, ISM devices thatuse the entirety of the ISM band (e.g., from 2401 through approximately2480 MHz) will employ filters that rollover into the neighboring band 40and band 7 and may cause interference.

In-device coexistence problems can exist with respect to a UE betweenresources such as, for example, LTE and ISM bands (e.g., forBluetooth/WLAN). In current LTE implementations, any interference issuesto LTE are reflected in the downlink measurements (e.g., ReferenceSignal Received Quality (RSRQ) metrics, etc.) reported by a UE and/orthe downlink error rate which the eNB can use to make inter-frequency orinter-RAT handoff decisions to, e.g., move LTE to a channel or RAT withno coexistence issues. However, it can be appreciated that theseexisting techniques will not work if, for example, the LTE uplink iscausing interference to Bluetooth/WLAN but the LTE downlink does not seeany interference from Bluetooth/WLAN. More particularly, even if the UEautonomously moves itself to another channel on the uplink, the eNB canin some cases handover the UE back to the problematic channel for loadbalancing purposes. In any case, it can be appreciated that existingtechniques do not facilitate use of the bandwidth of the problematicchannel in the most efficient way.

Turning now to FIG. 10, a block diagram of a system 1000 for providingsupport within a wireless communication environment for multi-radiocoexistence management is illustrated. In an aspect, the system 1000 caninclude one or more UEs 1010 and/or eNBs 1040, which can engage inuplink and/or downlink communications, and/or any other suitablecommunication with each other and/or any other entities in the system1000. In one example, the UE 1010 and/or eNB 1040 can be operable tocommunicate using a variety resources, including frequency channels andsub-bands, some of which can potentially be colliding with other radioresources (e.g., a broadband radio such as an LTE modem). Thus, the UE1010 can utilize various techniques for managing coexistence betweenmultiple radios utilized by the UE 1010, as generally described herein.

To mitigate at least the above shortcomings, the UE 1010 can utilizerespective features described herein and illustrated by the system 1000to facilitate support for multi-radio coexistence within the UE 1010.For example, a channel monitoring module 1012, a channel qualityreporting module 1014, and a channel reporting adjustment module 1016may be implemented. The channel monitoring module 1012 monitors theperformance of communication channels for potential interference issues.The channel quality reporting module 1014 reports on the quality ofcommunication channels. The channel reporting adjustment module 1016 mayadjust the reporting on the quality of communication channels using themethods described below. The various modules 1012-1016 may, in someexamples, be implemented as part of a coexistence manager such as theC×M 640 of FIG. 6. The various modules 1012-1016 and others may beconfigured to implement the aspects discussed herein.

FIG. 11 is a block diagram of a multi-radio wireless device 1100according to one aspect of the disclosure. As FIG. 11 illustrates, thewireless device 600 includes a mobile wireless services (MWS) radioaccess technology (MWS RAT) 1120 a and a wireless connectivity network(WCN) radio access technology (WCN RAT) 1120 b that are coupled toantennas 1110 a and 1110 b, respectively. In this configuration, the MWSRAT 1120 a may be an LTE RAT and the WCN RAT 1120 b may be a Bluetooth(BT) or Wireless local area network (WLAN) RAT that operates within theISM band. It should be appreciated, however, that the MWS RAT 1120 a isnot limited to LTE and could be another radio access technologiesincluding WiMAX and other like mobile wireless service technologies. Itshould also be appreciated that respective RATs 1120 can be coupled toany number of antennas 1110 and that multiple RATs 1120 can also share agiven antenna 1110.

In this configuration, the multi-radio wireless device 1100 includes acoexistence interface 1130 according to, for example, a universalasynchronous receiver/transmitter (UART). Representatively, thecoexistence interface 1130 is configured as a two-wire asynchronous,message based serial interface. A UART word format for communicationover the coexistence interface 1130 is shown in Table 1. The messagetypes communicated over the coexistence interface 1130 are shown inTable 2.

TABLE 1 LTE Coexistence UART Word Format b0 b1 b2 b3 b4 b5 b6 b7 Type[0]Type[1] Type[2] MSG[0] MSG[1] MSG[2] MSG[3] MSG[4]

TABLE 2 LTE Coexistence UART Message Types Message Type Message TypeDirection Indicator Real Time Signaling Message MWS <−> BT 0x00Transport Control Message MWS <−> BT 0x01 Transparent Data Message MWS<−> BT 0x02 MWS Inactivity Duration Message MWS −> BT 0x03 MWS ScanFrequency Message MWS −> BT 0x04 RFU MWS <− BT 0x03, 0x04 RFU 0x5 VendorSpecific 0x6-0x7

The Real Time Signaling Message is a bi-directional communicationmessage that provides a real time status report between the MWS RAT 1120a and WCN RAT 1120 b (e.g., when the MWS RAT 1120 a or the WCN RAT 1120b is transmitting or receiving, this status is communicated to the otherRAT). The Transport Control Message is a bi-directional message thatenables the request of a Real Time Signaling Message. For example, whenthe MWS RAT 1120 a awakes from a sleep state, a Transport ControlMessage may be issued to determine a real time status of the WCN RAT1120 b. The Transport Control Message is a bi-directional message thatenables the request of a Real Time Signaling Message. For example, whenthe MWS RAT 1120 a awakes from a sleep state, a Transport ControlMessage may be issued to determine a real time status of the WCN RAT1120 b. Transparent Data Messages contain data payload and are generatedby higher-layer protocols.

As further illustrated in Table 2, the MWS Inactivity Duration Messageis a unidirectional message from the MWS RAT 1120 a to the WCN RAT 1120b that provides a sleep indication duration. The MWS Scan FrequencyMessage is a unidirectional message from MWS RAT 1120 a to the WCN RAT1120 b to notify the WCN RAT 1120 b that the MWS RAT 1120 a isperforming a frequency scan.

As shown in FIG. 11, the MWS RAT 1120 a and the WCN RAT 1120 b arecollocated. Consequently, collocated interference 1102 is experiencedwhen the MWS RAT 1120 a and the WCN RAT 1120 b operate on adjacentbands. For example, the MWS RAT 1120 a may be an LTE modem and the WCNRAT 1120 b may be a BT or WLAN modem that operates within the ISM band.As noted in FIG. 9, WCN (e.g., BT and WLAN) and MWS (e.g., an LTE modem)radio access technologies operate on adjacent bands, resulting in thecollocated interference 1102 shown in FIG. 11.

As explained in FIG. 9 and shown in FIG. 11, interference may occur whenthe WCN RAT 1120 b (e.g., an Industrial, Scientific, and Medical (ISM)radio) receives at the same time the MWS RAT 1120 a in the device usinga proximate frequency bandwidth (e.g., a Long Term Evolution (LTE)radio) transmits. Similarly, interference may occur when the MWS RAT1120 a receives and the WCN RAT 1120 b transmits. To reduce theinterference and manage inter-radio coexistence, it is desirable tocoordinate behavior of the radios to reduce the time one radio isreceiving while another, potentially interfering, radio is transmitting.One aspect of the present disclosure manipulates the MWS channel stateinformation reporting to improve coexistence between MWS and WCN radioaccess technologies.

As shown in FIG. 11, the multi-radio wireless device 1100 may beconfigured to report measurement information (e.g., channel stateinformation (CSI)) to control the MWS RAT 1120 a of the multi-radiowireless device 1100. In one configuration, the multi-radio wirelessdevice 1100 transmits reports using an uplink control channel such as aphysical uplink control channel (PUCCH). The reports transmitted on theuplink may include channel quality indicators (CQI), precoding matrixindicators (PMI), rank indicators (RI), hybrid automatic repeat request(HARM), acknowledgement (ACK/NACK), channel status reports (CQI/PMI/RI),scheduling requests (SR) and sounding reference signals (SRS). Fordifferent reporting types, the PUCCH carries different indicators.

In LTE, the UE (e.g., multi-radio wireless device 1100) may beconfigured to report downlink channel state information to the servingeNodeB (evolved Node B). LTE supports both periodic and aperiodic (orevent triggered) reporting of channel state information (CSI), e.g.,CQI, PMI (precoding matrix indicator), PTI (precoding type indicator),and RI (rank indicator). Periodic reporting of CSI occurs for only onedownlink component carrier in one subframe. Both aperiodic and periodicreports are transmitted on a physical uplink shared channel (PUSCH),while only periodic reports are transmitted on the PUCCH.

When configured, the UE sends a CQI index that the eNodeB can use toderive a modulation and coding scheme (MCS) for downlink assignments.The UE may be configured to send sub-band or wide-band CQI reports.Sub-band reports specify two parameters: the sub-band, within thebandwidth part, that the UE prefers and the MCS for that sub-band, forexample, as shown FIG. 12.

FIG. 12 is a diagram 1200 illustrating sub-band and wideband CQIreporting. Representatively, a sub-band CQI report for sub-band number 0specifies a sub-band 1210 selected by the UE within the bandwidth part1202 the UE prefers and the MCS for that sub-band 1210. That is, the UEreports a preferred sub-band 1210 within the bandwidth part 1202 and achannel state index for the bandwidth part 1202. As further shown inFIG. 12, the UE cycles through the sub-band reports for sub-bands numberone and two followed by a wideband CQI report. This process repeats.

In one aspect of the disclosure, the MWS RAT 1120 a channel stateinformation reporting is manipulated to improve coexistence between MWSand WCN radio access technologies of the multi-radio wireless device1100. In one configuration, when the WCN RAT 1120 b intends to transmit,the MWS RAT 1120 a sends a fake CQI index to the network. The networkwill likely assign resources on other parts of the downlink bandwidthand leave this sub-band unused (making it possible for the WCN RAT 1120b to transmit). Table 3 shows the various CQI indices, and correspondingmodulation, code rate and efficiency. This aspect of the disclosurepresumes that the MWS RAT 1120 a has been configured by the eNodeB tosend sub-band signal quality reports, such as CQI reports.

TABLE 3 CQI Index modulation code rate x 1024 efficiency 0 out of range1 QPSK 78 0.1523 2 QPSK 120 0.2344 3 QPSK 193 0.3770 4 QPSK 308 0.6016 5QPSK 449 0.8770 6 QPSK 602 1.1758 7 16QAM 378 1.4766 8 16QAM 490 1.91419 16QAM 616 2.4063 10 64QAM 466 2.7305 11 64QAM 567 3.3223 12 64QAM 6663.9023 13 64QAM 772 4.5234 14 64QAM 873 5.1152 15 64QAM 948 5.5547

In one aspect of the disclosure, CQI index 0 (out-of-range) is sent whenthe WCN RAT 1120 b (e.g., WLAN) prefers that the MWS RAT 1120 a (e.g.,LTE) stay away from the entire sub-band (e.g., bandwidth part 1202). Inan alternative configuration, manipulation of the CQI reporting isapplied to a sub-set of a sub-band. For example, the MWS RAT 1120 a maylimit a CQI calculation to a sub-set of the sub-band that is apredetermined distance from the WCN (e.g., ISM) band, for example, asshown in FIG. 13.

FIG. 13 is a diagram 1300 illustrating manipulation of sub-band and CQIreporting to improve coexistence between MWS and WCN radio accesstechnologies according to one aspect of the disclosure. In oneconfiguration, a ten megahertz (10 MHz) system bandwidth is presumed. Inthis configuration, the MWS RAT 1120 a sends a CQI report index of 0 tosuggest that the base station avoid the entire sub-band (e.g., sub-band0, bandwidth part 1302) because the WCN RAT 1120 b is using thebandwidth part. As a result, the base station uses bandwidth part 1 orbandwidth part 2 to send data to the MWS RAT 1120 a, while avoidingsub-band 0, bandwidth part 1302.

In another configuration, the MWS RAT 1120 a may determine that apreferred sub-band 1310 within the bandwidth part 1302 is apredetermined distance from the WCN band. In this configuration, the MWSRAT 1120 a limits its search to a sub-set of the bandwidth part 1302that is a predetermined distance from the WCN band within the bandwidthpart 1302. In this configuration, the MWS RAT 1120 a sends a true CQIindex for the preferred sub-band 1310 within the searched sub-set. Thepreferred sub-band 1310 may be determined according to a peak of achannel frequency response within the bandwidth part 1302, for example.The channel frequency response may be masked to avoid the portion thatis within a predetermined proximity of the WCN band. The predetermineddistance from the WCN band within the bandwidth part 1302 may bedetermined according to a filter of the WCN RAT 1120 b that filterseither MWS interference or WCN interference to MWS.

FIG. 14 is a block diagram 1400 illustrating another aspect of thepresent disclosure. The block diagram 1400 includes subframes 1402 andresource blocks 1404. In this aspect, an exemplary modification of asounding reference signal (SRS) manipulates uplink scheduling grants. Inthis aspect, some subframes 1402 have SRS and some other subframes 1402do not have SRS. In one aspect, a program, function, operation or toolmay determine which subframe 1402 should transmit SRS and which subframe1402 should not transmit SRS. For the resource blocks 1404, thecombination of the system bandwidth, the SRS bandwidth configuration(C_SRS), and the SRS bandwidth (B_SRS) may determine how many resourceblocks should be used to carry the SRS. A sounding reference signal canbe modified for manipulating uplink scheduling grants to improvecoexistence between MWS and WCN radio access technologies. In LTE, theuplink SRS is spread across the frequency axis (except the scheduledPUCCH). The SRS may be used by the eNodeB to schedule the uplink grantsfor the UE. When SRS is configured, the MWS RAT 1120 a can reduce thetransmit power on portions of the SRS bandwidth that are close to theWCN channel of the WCN RAT 1120 b. In this configuration, the eNodeBestimates a bad channel response on that part of the bandwidth. That is,the reduced transmit power on the portions of the SRS bandwidth that areclose to the WCN channel discourage the eNodeB from allocating futureuplink assignments on those resources.

FIG. 15A is a flow chart illustrating a method 1500 for manipulatingsub-band and CQI reporting to improve coexistence between MWS and WCNradio access technologies according to one aspect of the presentdisclosure. As shown in FIG. 15A, a UE may alter a channel qualityindication or a channel quality state indication report to create asub-band communication gap in a first radio access technology, as shownin block 1510. A UE may communicate using a second radio accesstechnology during the sub-band communication gap, as shown in block1512.

In one aspect, whenever a first radio access technology receives apayload for transmission, it may buffer that payload until the nextchannel quality information reporting period occurs for a second radioaccess technology (such as LTE). At this time, a low channel qualityinformation index (such as zero) is sent for the second RAT. This lowchannel quality information index ensures that the second RAT will haveno downlink grants. The first RAT will then drain its buffer and willthen send an indication to the second RAT to start sending true channelquality information indices, that may not be low or zero.

FIG. 15B is a flow chart illustrating a method 1520 for adapting thechannel quality information reporting process according to one aspect ofthe present disclosure. As shown in FIG. 15B, a UE may buffercommunication payload for a first radio access technology (RAT), asshown in block 1522. A UE may report a low channel quality informationindex for a RAT, as shown in block 1524. A UE may drain the buffer ofthe channel measurement report in the first radio access technology, asshown in block 1526. A UE may then send an indication to the secondradio access technology to start submitting true channel qualityinformation indices, as shown in block 1528.

In one aspect, when a first RAT (such as a WiFi connection/network)receives a MAC service data unit (MSDU), a second RAT (such as LTE) maystart to send hybrid automatic repeat request (HARQ) negativeacknowledgment (NACK) signals regardless of actual downlink decodingresults, thus indicating failed communications to the second RAT basestation. The second RAT base station may then cause the second RAT toschedule aperiodic or periodic CQI reports for the UE. The UE may thenuse the methods described herein (including the methods disclosed inFIGS. 15A-15B) to influence a downlink allocation mechanism of thenetwork.

In one aspect, the second RAT sends HARQ NACK signals only when it isgranted downlink physical resource blocks (PRBs) that are close to RBsbeing used by a first RAT (such as WiFi). This may be applicable whetheror not CQI reporting is configured by the network.

In one aspect, a second RAT (such as LTE) characterizes the networkreaction to channel quality information indices. For example, second RATmay determine how long it takes for the network to downgrade downlinkmodulation and coding scheme (MCS) indices once the UE reports a lowCQI. In other words, after block 1524 of FIG. 15B, the UE may determinethe time it takes for the network to downgrade downlink MCS indices. ARAT (such as WiFi) may then use this determined time information for itsown traffic shaping purposes. For example, this characterization may beused to determine how long in advance and for how many times a low CQIreport has to be sent before a RAT such as WiFi can have access to themedium.

Overall, the channel quality information reporting process is madeadaptive by the above described approaches, so that various conditionsof a number of different radio access technologies may be exploited.

FIG. 16 is a diagram illustrating an example of a hardwareimplementation for an apparatus 1600 employing a multi-radio coexistencesystem 1614. The multi-radio coexistence system 1614 may be implementedwith a bus architecture, represented generally by a bus 1624. The bus1624 may include any number of interconnecting buses and bridgesdepending on the specific application of the multi-radio coexistencesystem 1614 and the overall design constraints. The bus 1624 linkstogether various circuits including one or more processors and/orhardware modules, represented by a processor 1626, an altering module1602, a communicating module 1604, a buffer modifying module 1606, achannel quality information reporting module 1608, and acomputer-readable medium 1628. The bus 1624 may also link various othercircuits such as timing sources, peripherals, voltage regulators, andpower management circuits, which are well known in the art, andtherefore, will not be described any further.

The apparatus includes the multi-radio coexistence system 1614 coupledto a transceiver 1622. The transceiver 1622 is coupled to one or moreantennas 1620. The transceiver 1622 provides a means for communicatingwith various other apparatus over a transmission medium. The multi-radiocoexistence system 1614 includes the processor 1626 coupled to thecomputer-readable medium 1628. The processor 1626 is responsible forgeneral processing, including the execution of software stored on thecomputer-readable medium 1628. The software, when executed by theprocessor 1626, causes the multi-radio coexistence system 1614 toperform the various functions described supra for any particularapparatus. The computer-readable medium 1628 may also be used forstoring data that is manipulated by the processor 1626 when executingsoftware. The multi-radio coexistence system 1614 further includes thealtering module 1602 for altering a channel measurement report to createa sub-band communication gap in a first radio access technology and thecommunicating module 1604 for communicating using a second radio accesstechnology during the sub-band communication gap. The multi-radiocoexistence system 1614 additionally includes the buffer modifyingmodule 1606 for creating a buffer for a channel measurement report in afirst radio access technology, and for draining the buffer of thechannel measurement report in the first radio access technology. Themulti-radio coexistence system 1614 further includes the channel qualityinformation reporting module 1608 for reporting a low channel qualityinformation index during a reporting period for a second radio accesstechnology and for sending an indication to the second radio accesstechnology to start submitting true channel quality information indices.The altering module 1602, the communicating module 1604, the buffermodifying module 1606, and the channel quality information reportingmodule 1608 may be software modules running in the processor 1626,resident/stored in the computer readable medium 1628, one or morehardware modules coupled to the processor 1626, or some combinationthereof. The multi-radio coexistence system 1614 may be a component ofthe UE 250 and may include the memory 272 and/or the processor 270.

In one configuration, the apparatus 1600 for wireless communicationincludes means for altering a channel measurement report to create asub-band communication gap in a first radio access technology. The meansmay be the altering module 1602 and/or the multi-radio coexistencesystem 1614 of the apparatus 1600 configured to perform the functionsrecited by the altering means. As described above, the multi-radiocoexistence system 1614 may include means for communicating using asecond radio access technology during the sub-band communication gap.The means may be the communicating module 1604 and/or the multi-radiocoexistence system 1614 of the apparatus 1600 configured to perform thefunctions recited by the measuring and recording means As describedabove, the multi-radio coexistence system 1614 may also include meansfor creating a buffer for a channel measurement report in a first radioaccess technology and for draining the buffer of the channel measurementreport in the first radio access technology. The means may be the buffermodifying module 1606 and/or the multi-radio coexistence system 1614 ofthe apparatus 1600 configured to perform the functions recited by thebuffer modifying means. As described above, the multi-radio coexistencesystem 1614 may also include means for reporting a low channel qualityinformation index during a reporting period for a second radio accesstechnology and for sending an indication to the second radio accesstechnology to start submitting true channel quality information indices.The means may be the channel quality information reporting module 1608and/or the multi-radio coexistence system 1614 of the apparatus 1600configured to perform the functions recited by the channel qualityinformation reporting means. In another aspect, the aforementioned meansmay be any module or any apparatus configured to perform the functionsrecited by the aforementioned means.

The examples above describe aspects implemented in an LTE system.However, the scope of the disclosure is not so limited. Various aspectsmay be adapted for use with other communication systems, such as thosethat employ any of a variety of communication protocols including, butnot limited to, CDMA systems, TDMA systems, FDMA systems, and OFDMAsystems.

It is understood that the specific order or hierarchy of steps in theprocesses disclosed is an example of exemplary approaches. Based upondesign preferences, it is understood that the specific order orhierarchy of steps in the processes may be rearranged while remainingwithin the scope of the present disclosure. The accompanying methodclaims present elements of the various steps in a sample order, and arenot meant to be limited to the specific order or hierarchy presented.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the aspects disclosed herein may be implemented aselectronic hardware, computer software, or combinations of both. Toclearly illustrate this interchangeability of hardware and software,various illustrative components, blocks, modules, circuits, and stepshave been described above generally in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system. Skilled artisans may implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such the processorcan read information from, and write information to, the storage medium.In the alternative, the storage medium may be integral to the processor.The processor and the storage medium may reside in an ASIC. The ASIC mayreside in a user terminal. In the alternative, the processor and thestorage medium may reside as discrete components in a user terminal.

The previous description of the disclosed aspects is provided to enableany person skilled in the art to make or use the present disclosure.Various modifications to these aspects will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other aspects without departing from the spirit or scope ofthe disclosure. Thus, the present disclosure is not intended to belimited to the aspects shown herein but is to be accorded the widestscope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method of wireless communication, comprising:buffering communications for a first radio access technology (RAT);reporting a low channel quality for a second RAT; receiving anindication to halt second RAT downlink communications based on thereported low channel quality; transmitting the buffered communicationsby the first RAT when the second RAT downlink communications are halted;and sending an indication to the second RAT to resume normal channelquality reporting.
 2. The method of claim 1, further comprisingdetermining when first RAT communications will occur on resource blocksneighboring second RAT communications, and in which the reporting isbased at least in part on the determining.
 3. A method of wirelesscommunication, comprising: detecting when potential communicationtime/frequency resources of a second radio access technology (RAT) arewithin a threshold distance to communication time/frequency resources ofa first RAT; reporting an altered channel quality for the potentialcommunication time/frequency resources of the second RAT when thepotential communication time/frequency resources of the second RAT arewithin the threshold distance; and communicating on the time/frequencyresources of the first RAT.
 4. The method of claim 3, in which thereporting the altered channel quality comprises reporting a channelquality information index of zero.
 5. The method of claim 3, in whichthe detecting comprises detecting when the potential communicationtime/frequency resources of the second RAT overlap with a bandwidth usedby the first RAT.
 6. An apparatus for wireless communication comprising:means for buffering communications for a first radio access technology(RAT); means for reporting a low channel quality for a second RAT; meansfor receiving an indication to halt second RAT downlink communicationsbased on the reported low channel quality; means for transmitting thebuffered communications by the first RAT when the second RAT downlinkcommunications are halted; and means for sending an indication to thesecond RAT to resume normal channel quality reporting.
 7. The apparatusof claim 6, further comprising means for determining when first RATcommunications will occur on resource blocks neighboring second RATcommunications, and in which the reporting means is based at least inpart on the determining means.
 8. An apparatus for wirelesscommunication, comprising: means for detecting when potentialcommunication time/frequency resources of a second radio accesstechnology (RAT) are within a threshold distance to communicationtime/frequency resources of a first RAT; means for reporting an alteredchannel quality for the potential communication time/frequency resourcesof the second RAT when the potential communication time/frequencyresources of the second RAT are within the threshold distance; and meansfor communicating on the time/frequency resources of the first RAT. 9.The apparatus of claim 8, in which the means for reporting the alteredchannel quality comprises means for reporting a channel qualityinformation index of zero.
 10. The apparatus of claim 8, in which themeans for detecting comprises means for detecting when the potentialcommunication time/frequency resources of the second RAT overlap with abandwidth used by the first RAT.
 11. A computer program product forwireless communication in a wireless network, comprising: anon-transitory computer-readable medium having non-transitory programcode recorded thereon, the program code comprising: program code tobuffer communications for a first radio access technology (RAT); programcode to report a low channel quality for a second RAT; program code toreceive an indication to halt second RAT downlink communications basedon the reported low channel quality; program code to transmit thebuffered communications by the first RAT when the second RAT downlinkcommunications are halted; and program code to send an indication to thesecond RAT to resume normal channel quality reporting.
 12. The computerprogram product of claim 11, further comprising program code todetermine when first RAT communications will occur on resource blocksneighboring second RAT communications, and in which the program code toreport is based at least in part on the program code to determine.
 13. Acomputer program product for wireless communication in a wirelessnetwork, comprising: a non-transitory computer-readable medium havingnon-transitory program code recorded thereon, the program codecomprising: program code to detect when potential communicationtime/frequency resources of a second radio access technology (RAT) arewithin a threshold distance to communication time/frequency resources ofa first RAT; program code to report an altered channel quality for thepotential communication time/frequency resources of the second RAT whenthe potential communication time/frequency resources of the second RATare within the threshold distance; and program code to communicate onthe time/frequency resources of the first RAT.
 14. The computer programproduct of claim 13, in which the program code to report the alteredchannel quality comprises program code to report a channel qualityinformation index of zero.
 15. The computer program product of claim 13,in which the program code to detect comprises program code to detectwhen the potential communication time/frequency resources of the secondRAT overlap with a bandwidth used by the first RAT.
 16. An apparatus forwireless communication, comprising: a memory; at least one processorcoupled to the memory, the at least one processor being configured: tobuffer communications for a first radio access technology (RAT); toreport a low channel quality for a second RAT; to receive an indicationto halt second RAT downlink communications based on the reported lowchannel quality; to transmit the buffered communications by the firstRAT when the second RAT downlink communications are halted; and to sendan indication to the second RAT to resume normal channel qualityreporting.
 17. The apparatus of claim 16, in which the at least oneprocessor is further configured to determine when first RATcommunications will occur on resource blocks neighboring second RATcommunications, and in which the at least one processor being configuredto report is based at least in part on the at least one processor beingconfigured to determine.
 18. An apparatus for wireless communication,comprising: a memory; at least one processor coupled to the memory, theat least one processor being configured: to detect when potentialcommunication time/frequency resources of a second radio accesstechnology (RAT) are within a threshold distance to communicationtime/frequency resources of a first RAT; to report an altered channelquality for the potential communication time/frequency resources of thesecond RAT when the potential communication time/frequency resources ofthe second RAT are within the threshold distance; and to communicate onthe time/frequency resources of the first RAT.
 19. The apparatus ofclaim 18, in which the at least one processor being configured to reportthe altered channel quality comprises the at least one processor beingconfigured to report a channel quality information index of zero. 20.The apparatus of claim 18, in which the at least one processor beingconfigured to detect comprises the at least one processor beingconfigured to detect when the potential communication time/frequencyresources of the second RAT overlap with a bandwidth used by the firstRAT.